The probability of 1 in a million is for a different face to be similar enough to yours to unlock. Unless there are 999 999 other people picking up your phone every day (which would be over 10 people per second), it will essentially never happen.
Also, phone requires passcode after X failed attempts, so even then you can could only try <10 other faces.
If we ignore the twin case, since that doesn’t apply to most people, as long as the odds are better than 1:50,000 it’s still just as good or better than TouchID.
Also, phone requires passcode after X failed attempts, so even then you can could only try <10 other faces.